The importance of maintaining the surface of highways, driveways, parking lots, and airports is important. Many businesses rely upon integrity of paved surfaces. However, if not maintained properly, the integrity may be compromised leading to catastrophic failure of the paved surface. Generally, when asphalt or other paving materials are laid down as a new product or as an overlay, it begins to deteriorate immediately under ambient conditions like, the weather, bearing loads e.g. trucks, cars, airplanes, construction equipment along with changing underground conditions like erosion, contour shifting and ground or underground water. Eventually, if the pavement is not cared for properly, it will fail, forming cracks of different sizes. Water infiltration is a common cause of crack formation. This is particularly troublesome when the cracks form along the interior paved surface. Cracks located within the interior paved surface tend to accelerate degeneration of the paved surface and may ultimately result in structural failure. Therefore, it is important to maintain the integrity of the paved surface, including minimizing the impact of ground or underground water.
If the asphalt has not been maintained properly traffic or any other asphalt load bearing condition may more easily lead to cracks within the asphalt or may provide a weakened condition conducive to crack formation.
Seams formed in the asphalt laying process may constitute another problem. Due to freezing, temperature change, or excess water allowed through the seams as well as other weather phenomena, the seam may eventually (within a year or two), depending on the sub-base, open up and leave a crack in the asphalt which usually runs along the seam. If the crack in the seam is not sealed within a reasonable period of time, water (from rain, snow, and other precipitation) may find its way underneath the asphalt between the layers of the asphalt. Changes in temperature, i.e., intermittent freezing and thawing, destruct the asphalt frames which also advances the deterioration process of the asphalt.
It is a known practice to fill cracks with sealers to repair the cracks in order to prevent further deterioration of the asphalt. Products such as commercially available rubberized asphalt, silicone rubber, coal tar, PVC, and neoprene have been used to repair cracks in pavements. Among the many techniques for sealing cracks in pavement two main methods have been typically used.
One of the commercially used methods is a hot pour crack filling, where a sealing compound is heated and melted from a relatively solid brick state into a liquid state and maintained in a container with an oil jacket to insulate against heat loss. Being in a liquid stage the sealer is pumped into the crack through a hose and is applied around the crack as well as over the crack area. The machines for applying sealant to the crack using the hot pour crack filling method are relatively expensive, with the cost possibly ranging from $5,000.00 to $25,000.00. The process is extremely time consuming, because it takes about an hour to an hour and a half to heat the block of sealer to transform it into a liquid form, then the liquefied sealant must be repeatedly transferred to a dispensing container and manually dispensed to the paved surface typically by hand or with a hose or machine having limited maneuverability. Because of the weight and heat of any handheld machines, the application of the crack sealer can be dangerous and time consuming.
Some crack sealers are maintained and dispersed at very high temperatures. In addition, as the crack sealer is dispensed, it often overflows or otherwise attaches to sidewalls of the machinery and is difficult to remove from associated surfaces. Because many crack sealers are combustible, one way to remove the undesired crack sealer involves combustion with an igniter such as a torch directed to the attached material. However, many machines may include materials which are not designed to sustain combustion necessary to remove the attached material and may inadvertently burn or become damaged. Therefore, there exists a need for a sealant dispenser which can withstand elevated temperatures.
A material which can sustain the elevated temperature is carbon steel. However, combined with the weight of the sealant and the weight of the steel, may cause difficulty for maneuvering the machine or otherwise transport it to areas necessary for repair or treatment of the paved surface. In addition, the terrain associated with the paved surface may be irregular as the paved surface has eroded. Centering the weight of the contained sealant and the balance of the machine may be important in avoiding accidents as the machine traverses the irregular surface. The machines ability to distribute the load over multiple wheels may be desirable. Difficulty in maneuverability and weight may increase the time necessary for repair or treatment of the paved surface which can also lead to increased costs and decreased efficiencies as well as additional safety issues related to working with the hot combustible material. Therefore, there exists a need for an easy to maneuver sealant dispenser which is adapted for traversing difficult terrain.
Crack sealing machines come in a variety of different styles, types, designs, and dollar factors. For example, a crack sealer machine, described in U.S. Pat. No. 6,290,428 includes a wheeled, supporting frame and a container for holding crack filler. U.S. Pat. No. 4,653,424 includes a wheeled support frame with a tank for dispensing the contained crack filling medium and a squeegee operably connected to handle for spreading the dispensed crack filler. Another machine for dispensing sealant into cracks in pavement, described in U.S. Pat. No. 4,575,279, includes a container mounted on a movable frame. The container has a dispensing opening in a bottom wall and a valve assembly in the container itself to control flow of sealant from the container. A roller and squeegee are mounted under the container for spreading the material after it has been dispensed. However, each of these machines had disadvantages which are addressed by the present invention, a sealant dispenser for dispensing and selectively spreading the sealant on the paved surface.